The Tomato NBARC-LRR Protein Prf Interacts with Pto Kinase in Vivo to Regulate Specific Plant Immunity

Mucyn, Tatiana S.; Clemente, Alfonso; Andriotis, Vasilios M. E.; Balmuth, Alexi L.; Oldroyd, Giles; Staskawicz, Brian J.; Rathjen, John P.

doi:10.1105/tpc.106.044016

Cited by 231 publications

(278 citation statements)

References 49 publications

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“…The previously proposed model (Xing et al, 2007) for how AvrPto-Pto interaction activates Prf signaling is thus also applicable to AvrPtoB. The direct target of Pto inhibition is likely Prf, based on the fact these two proteins directly interact (Mucyn et al, 2006). This interaction likely involves the interfaces used by Pto for AvrPtoB and AvrPto binding, as mutations at these sites generated CGF Pto mutants presumably through disturbing interaction with Prf.…”

Section: Discussionmentioning

confidence: 99%

“…Extensive mutational analysis and yeast two-hybrid (Y2H) studies have demonstrated that interaction between Pto and AvrPto or AvrPtoB is the molecular basis for pathogen recognition and activation of the immune response Tang et al, 1996;Kim et al, 2002). Prf, a protein with a nucleotide binding site and leucine-rich repeats, is required for Pto-mediated resistance to Pst (Salmeron et al, 1996), and Pto/Prf have been shown to occur in a complex in the plant cell (Salmeron et al, 1996;Mucyn et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

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Crystal Structure of the Complex between Pseudomonas Effector AvrPtoB and the Tomato Pto Kinase Reveals Both a Shared and a Unique Interface Compared with AvrPto-Pto

et al. 2009

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Resistance to bacterial speck disease in tomato (Solanum lycopersicum) is activated upon recognition by the host Pto kinase of either one of two sequence-unrelated effector proteins, AvrPto or AvrPtoB, from Pseudomonas syringae pv tomato (Pst). Pto induces Pst immunity by acting in concert with the Prf protein. The recently reported structure of the AvrPto-Pto complex revealed that interaction of AvrPto with Pto appears to relieve an inhibitory effect of Pto, allowing Pto to activate Prf. Here, we present the crystal structure of the Pto binding domain of AvrPtoB (residues 121 to 205) at a resolution of 1.9Å and of the AvrPtoB121-205–Pto complex at a resolution of 3.3 Å. AvrPtoB121-205 exhibits a tertiary fold that is completely different from that of AvrPto, and its conformation remains largely unchanged upon binding to Pto. In common with AvrPto-Pto, the AvrPtoB-Pto complex relies on two interfaces. One of these interfaces is similar in both complexes, although the primary amino acid sequences from the two effector proteins are very different. Amino acid substitutions in Pto at the other interface disrupt the interaction of AvrPtoB-Pto but not that of AvrPto-Pto. Interestingly, substitutions in Pto affecting this unique interface also cause Pto to induce Prf-dependent host cell death independently of either effector protein.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Crystal Structure of the Complex between Pseudomonas Effector AvrPtoB and the Tomato Pto Kinase Reveals Both a Shared and a Unique Interface Compared with AvrPto-Pto

et al. 2009

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“…The first evidence of that came from yeast twohybrid analyses of PM1-RIN4 interactions16. Subsequently, the amino-terminal portion of Prf was shown to be both necessary and sufficient for binding to Pto 33 . In addition, the coiled-coil domain of RPS5 is both necessary and sufficient for binding to PBS1 (J. Ade and R.W.I., unpublished data).…”

Section: Functions Of the Amino-terminal Domainmentioning

confidence: 99%

“…In contrast to the interactions of Rx, the presence of the cognate bacterial effector does not disrupt Bs2 intramolecular interactions but seems to stabilize them 74 . In addition, AvrPto fails to disrupt Pto-Prf interactions 33 . Further investigation is needed to clarify the function of pathogen effectors and their targets in plant NBS-LRR activation.…”

Section: Intramolecular Interactionsmentioning

confidence: 99%

Plant NBS-LRR proteins in pathogen sensing and host defense

2006

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Plant proteins belonging to the nucleotide-binding site-leucine-rich repeat (NBS-LRR) family are used for pathogen detection. Like the mammalian Nod-LRR protein 'sensors' that detect intracellular conserved pathogen-associated molecular patterns, plant NBS-LRR proteins detect pathogen-associated proteins, most often the effector molecules of pathogens responsible for virulence. Many virulence proteins are detected indirectly by plant NBS-LRR proteins from modifications the virulence proteins inflict on host target proteins. However, some NBS-LRR proteins directly bind pathogen proteins. Association with either a modified host protein or a pathogen protein leads to conformational changes in the amino-terminal and LRR domains of plant NBS-LRR proteins. Such conformational alterations are thought to promote the exchange of ADP for ATP by the NBS domain, which activates 'downstream' signaling, by an unknown mechanism, leading to pathogen resistance.Plants lack the adaptive immunity that vertebrates rely on to respond to pathogens. To successfully detect and ward off pathogens, plants must rely solely on genes stably encoded in the genome. Although the exact mechanisms of pathogen detection differ, plants, like animals, use two distinct defense 'systems' to recognize and respond to pathogen challenge 1 . Pathogen-associated molecular patterns (PAMPs), such as bacterial flagellin, lipopolysaccharides and fungal-oomycete cellulose-binding elicitor proteins, are recognized by plant transmembrane receptors that activate basal defense, a first line of defense against pathogens that is reminiscent of innate immunity in vertebrates 2, 3. In both plants and animals, it is hypothesized that a biological 'arms race' is occurring, in which pathogens have acquired mechanisms to evade PAMP-triggered immunity by evolving effector molecules that modify the state of the host cell, thereby bypassing or disrupting the first line of defense. Plant evolution has countered with proteins that detect specific effector molecules, a mechanism called 'effector-triggered immunity'1 that amounts to a second line of defense. Plant effector-triggered immunity is more akin to mammalian adaptive immunity in that pathogen effectors, rather than conserved elements such as PAMPs, are specifically recognized. However, unlike the situation in mammalian adaptive immunity, the plant host specificity determinants of effector-triggered immunity are encoded in every cell of an organism.The genes encoding the specificity determinants of effector-triggered immunity are known as resistance (R) genes. Most R genes encode proteins that contain a nucleotide-binding site (NBS) and leucine-rich repeats (LRRs). NBS-LRR proteins are involved in the recognition of specialized pathogen effectors (also called avirulence (Avr) proteins) that are thought to provide virulence function in the absence of the cognate R gene 1 . NBS-LRR proteins are also important in animal innate immune systems; however, in animals they seem to be involved in PAMP recognition rather th...

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“…Recently, it was shown that Pto associates with a unique Prf N-terminal domain and resides in a high-molecularweight recognition complex. In this complex, both Pto and Prf contribute to specific recognition of AvrPtoB (21).…”

mentioning

confidence: 99%

Proteolysis of the barley receptor-like protein kinase RPG1 by a proteasome pathway is correlated with Rpg1 -mediated stem rust resistance

Nirmala¹,

Dahl

Steffenson

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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In plants, disease resistance mediated by the gene-for-gene mechanism involves the recognition of specific effector molecules produced by the pathogen either directly or indirectly by the resistance-gene products. This recognition triggers a series of signals, thereby serving as a molecular switch in regulating defense mechanisms by the plants. To understand the mechanism of action of the barley stem rust resistance gene Rpg1, we investigated the fate of the RPG1 protein in response to infection with the stem rust fungus, Puccinia graminis f. sp. tritici. The investigations revealed that RPG1 disappears to undetectable limits only in the infected tissues in response to avirulent, but not virulent pathotypes. The RPG1 protein disappearance is rapid and appears to be due to specific protein degradation via the proteasome-mediated pathway as indicated by inhibition with the proteasomal inhibitor MG132, but not by other protease inhibitors.avirulence ͉ cultivar ͉ programmed cell death ͉ Puccinia graminis P lants have evolved diverse mechanisms to recognize pathogen attack and trigger defense responses. Pathogen recognition specificity is often determined by a pathogen avirulence (Avr) gene and its corresponding plant resistance (R) gene in a gene for gene manner (1). The R gene products may function directly or indirectly as receptors for the Avr gene products, providing detection of pathogen attack (2-6). Avr proteins secreted from the pathogen are recognized by the R proteins either in the intercellular spaces or after their transport into the plant cell. The Avr-R interactions lead to activation of defense responses and often result in the hypersensitive response (HR) (1), inhibiting the growth of the pathogen. In the absence of either the cognate R or Avr gene product, the pathogen colonizes the host and causes disease. Despite the cloning of several R genes and their corresponding Avr genes, direct physical interaction between matched Avr and R proteins has been shown only in a few cases. To exemplify, the Avr-Pita protein of the rice blast fungus Magnaporthe grisea encoding a metalloprotease is secreted with an N-terminal signal sequence. After delivery into the plant cell and removal of the proprotein sequence, the mature enzyme binds to the leucine-rich domain of the Pi-ta R protein and elicits the resistance response. This interaction was confirmed with the yeast two-hybrid system, with transient expression in rice seedling leaves of resistant or susceptible lines, by in vitro binding of the recombinantly synthesized Pi-ta protein to the Avr-Pita protein and by inactivation of either of the proteins through amino acid substitutions (7). Direct physical interaction has been demonstrated for the tomato Pto R protein and the AvrPto gene product (2, 4), the Arabidopsis RRS1 R and Ralstonia solanacearum PopP2 (8), and between the flax R gene L6 with the corresponding Avr-L6 of Melampsora lini (9). However, attempts with other R-Avr pairs have failed to establish a direct physical interaction. These observations ...

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The Tomato NBARC-LRR Protein Prf Interacts with Pto Kinase in Vivo to Regulate Specific Plant Immunity

Cited by 231 publications

References 49 publications

Crystal Structure of the Complex between Pseudomonas Effector AvrPtoB and the Tomato Pto Kinase Reveals Both a Shared and a Unique Interface Compared with AvrPto-Pto

Crystal Structure of the Complex between Pseudomonas Effector AvrPtoB and the Tomato Pto Kinase Reveals Both a Shared and a Unique Interface Compared with AvrPto-Pto

Plant NBS-LRR proteins in pathogen sensing and host defense

Proteolysis of the barley receptor-like protein kinase RPG1 by a proteasome pathway is correlated with Rpg1 -mediated stem rust resistance

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